The objective of this project is to purify ACh-receptors of housefly brain and cockroach ganglia, to compare their molecular properties with pure ACh-receptors from mammalian brain and electric organs of fish, and finally to prepare chemicals with high affinities for insect ACh-receptors and test them for insecticidal action. The first step will be the purification of insect ACh-receptors by means of affinity chromatography and their identification by equilibrium dialysis, using radiolabeled cholinergic ligands. The molecular weight and shape will be determined by column chromatography, sedimentation velocity and electron microscopy. The amino acids will be analyzed and the active groups assayed by active-site directed reagents. Antibodies to the pure receptor proteins will be produced in rabbits, radiolabeled and used to localize the ACh-receptors in the insect central nervous system. Chemicals will be synthesized and tested for their affinities to insect ACh-receptors and for their toxicity by topical application to house flies.